Swellable Member, Swell Controlling Arrangement and Method of Controlling Swelling of a Swellable Member

ABSTRACT

A swell controlling arrangement includes a swellable member configured to swell upon exposure to a swell inducing fluid, and an acidic material that is configured to form an acidic environment. The swell controlling arrangement is configured to preferentially expose the swellable member to the acidic environment when the swellable member and the acidic material are exposed to the swell inducing fluid.

BACKGROUND

Fluidic systems, such as, tubular systems employed in earth formation boreholes for purposes such as hydrocarbon recovery and carbon dioxide sequestration, for example, at times employ swellable members to create seals between tubulars. Such swellable members may swell in response to being exposed to fluids that induce swelling of the swellable member. Polymeric materials, including various elastomers, swell when exposed to water, oil, brine and natural gas, for example. The swellable material itself largely controls the rate of swelling of members made of the material once exposure to a swell inducing fluid has been initiated. This natural swell rate, however, can progress at unpredictable rates that can sometimes interfere with operations. Since greater control is always a goal for operators in the downhole industry, inventions providing such control are always well received.

BRIEF DESCRIPTION

Disclosed herein is a swell controlling arrangement that includes a swellable member configured to swell upon exposure to a swell inducing fluid, and an acidic material that is configured to form an acidic environment. The swell controlling arrangement is configured to preferentially expose the swellable member to the acidic environment when the swellable member and the acidic material are exposed to the swell inducing fluid.

Also disclosed herein is a swell controlling arrangement that includes a swellable member configured to swell in a swell inducing fluid, and an acid forming material disposed at the swellable member configured to form acid that is preferentially exposed to the swellable member over the swell inducing fluid.

Further disclosed is a method of controlling swelling of a swellable member. The method includes, forming an acidic environment, exposing a swellable member to the acidic environment, and positioning the swellable member and the acidic environment within a swell inducing fluid.

Further disclosed is a swellable member including a polymeric body configured to swell upon exposure to a swell inducing fluid, and an acidic material disposed at the polymeric body configured to retard a rate of swelling when the polymeric body is exposed to the swell inducing fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 depicts a cross sectional view of a swell controlling arrangement depicted herein;

FIG. 2 depicts a cross sectional view of an alternate embodiment of a swell controlling arrangement disclosed herein;

FIG. 3 depicts a partial cross sectional view of a portion of a swellable member disclosed herein; and

FIG. 4 depicts a partial cross sectional view of a portion of an alternate swellable member disclosed herein.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed arrangement, apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring to FIG. 1, an embodiment of a swell controlling arrangement disclosed herein is illustrated generally at 10. The swell controlling arrangement 10 includes, a swellable member 14, disclosed in this embodiment as an acrylate polymer, and an acidic material 18. The acidic material 18 may be in the form of an acidic fluid, acidic crystals, or a chemical that reacts to form an acidic environment 20. The polymeric swellable member 14 is configured to swell in response to exposure to a swell inducing fluid 22. In this embodiment the swell controlling arrangement 10 is employed within a borehole 26 in an earth formation 30. The polymeric swellable member 14 is designed to occlude an annular space 34 defined between an outer surface 38 of a tubular 42 and an inner surface 46 of the borehole 26 when in a swelled condition. The swellable member 14 is illustrated in the Figure in an unswelled condition. By sealingly engaging with the surfaces 38 and 46 the swellable member 14 can fully plug the annular space 34.

The polymeric swellable member 14 of this embodiment, being an acrylate polymer, swells at a rate in response to exposure to, water, oil, brine, natural gas and combinations of two or more of the foregoing. The polymeric swellable member 14 swells at a slower rate when preferentially exposed to an acidic environment 20. This reduction in swell rate is particularly pronounced when the acidic environment 20 includes an organic acid, such as one or more of, lactic acid, acetic acid, formic acid, citric acid, oxalic acid and uric acid, and the acidic environment 20 has a pH level in the range of 3 to 6. As such the swell controlling arrangement 10 disclosed herein retards the swelling or, stated another way, it slows a rate of swelling.

The swell controlling arrangement 10, as illustrated in FIG. 1, preferentially exposes the swellable member 14, to the acidic environment 20 over the swell inducing fluid 22. In this embodiment, the preferential exposure is caused by a film 50 that is strapped to the tubular 42 at opposite ends 54, 58 of the swellable member 14 by bands 62. The film 50 slows a rate of dilution of pH of the acidic environment 20, thereby retarding swell of the swellable member 14. The film 50 is not constructed to completely prevent exposure of the swellable member 14 to the swell inducing fluid 22, but instead is intentionally made to delay or meter that rate of such exposure. The film 50 may be permeable to the swell inducing fluid 22 such that the fluid 22 is able to pass directly through the film 50 at a controlled rate. Alternately, the film 50 could be configured to allow the fluid 22 to essentially flow around the film 50 via the ends 54, 58, or between layers (not shown) of the film 50 wherein the film 50 is rolled upon itself. The film 50 also may be dissolvable within the swell inducing fluid 22 over a period of time. Regardless of the mechanism whereby the fluid 22 breaches the film 50, once the fluid 22 is between the film 50 and the swellable member 14 it causes dilution of the acidic environment 20 and induces swelling of the swellable member 14 at a faster rate. An operator can, therefore, control a rate of swelling of the swellable member 14 now through control of dilution of the acidic environment 20 via construction parameters of the film 50. In an alternate embodiment, the acidic material 18 could be positioned within layers of the film 50, or could be embedded into the film 50 directly. A quantity of the acidic material 18 initially employed can be established to engineer the amount of retardation.

Additionally, dilution of the acidic environment 20, and a corresponding change in swell rate, could be made to accelerate upon rupturing of the film 50. The film 50 could be made to rupture when the swellable member 14 has swelled to a selected size. Such a configuration would provide an operator with additional control over timing associated with fully swelling the swellable member 14. In order to assure integrity of the film 50 until rupturing is desired, the film 50 can be protected from abrasion during running into the borehole 26 through such things as being radially dimensionally smaller than surfaces longitudinally adjacent thereto, for example.

Referring to FIG. 2, an alternate embodiment of a swell controlling arrangement is illustrated at 110. The arrangement 110 employs nozzles 116 that are configured to discharge an acidic material 120 at a swellable member 114. In this embodiment the acidic material 120 is housed in chambers 124. Pistons 130, slidably sealingly engaged with the chambers 124 are moved to cause the acidic material 120 housed therewithin to discharge through the nozzles 116 near the swellable member 114. Depending upon the application, surrounding structures, such as a borehole wall 134 and a basepipe 138, could, in the case of a downhole application, define a volume (i.e. an annular space 142) that limits dilution rates of the acid 120 once discharged therein. The acidic material 120 can itself be an acid, or can be a material configured to form an acid upon expose to some other material. For example, the acidic material 120 may be acidic crystals that are solutionized in a fluid, such as the swell inducing fluid 22, to form the acidic environment 20.

Referring to FIGS. 3 and 4, alternate embodiments of a swellable member are illustrated at 214 and 314. The swellable members 214 and 314 differ from the swellable member 14 in that the acidic material 18 is embedded within the swellable members 214 and 314 as opposed to being external to the swellable members 214 and 314. In the swellable member 214, for example, the acidic material 18 is embedded in concentric layers 216. The swellable member 214, as illustrated, has three of the concentric layers 216, however any number of the layers 216 could be employed. Additionally, the layers 216 could be distributed in any orientation without deviating from the intent of the invention.

Referring specifically to FIG. 4, the swellable member 314 has the acidic material 18 distributed throughout the polymeric material that defines a majority of the swellable member 18. This embodiment may generate an even rate of swelling of the swellable member 314 since locations of the acidic material 18 relative to the polymeric material are uniformly distributed.

While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 

1. A swell controlling arrangement, comprising: a swellable member configured to swell upon exposure to a swell inducing fluid; and an acidic material being configured to form an acidic environment, the swell controlling arrangement being configured to preferentially expose the swellable member to the acidic environment when the swellable member and the acidic material are exposed to the swell inducing fluid.
 2. The swell controlling arrangement of claim 1, further comprising a film in operable communication with the acidic material and the swellable member configured to delay dilution of the acidic environment.
 3. The swell controlling arrangement of claim 2, wherein the film is permeable to the swell inducing fluid.
 4. The swell controlling arrangement of claim 2, wherein the film is dissolvable in the swell inducing fluid.
 5. The swell controlling arrangement of claim 2, wherein the film is protected from abrasion.
 6. The swell controlling arrangement of claim 1, wherein the acidic material is an organic acidic material.
 7. The swell controlling arrangement of claim 6, wherein the organic acidic material is selected from the group consisting of lactic acid, acetic acid, formic acid, citric acid, oxalic acid, uric acid and combinations of two or more of the foregoing.
 8. The swell controlling arrangement of claim 1, wherein the swellable member is a polymer.
 9. The swell controlling arrangement of claim 1, wherein the swellable member is an acrylate polymer.
 10. The swell controlling arrangement of claim 1, wherein the acidic material is embedded within the swellable member.
 11. The swell controlling arrangement of claim 1, wherein the acidic material is distributed in layers embedded within the swellable member.
 12. A swell controlling arrangement, comprising: a swellable member configured to swell in a swell inducing fluid; and an acid forming material disposed at the swellable member configured to form acid that is preferentially exposed to the swellable member over the swell inducing fluid.
 13. The swell controlling arrangement of claim 12, wherein the acid forming material is embedded within the swellable member.
 14. The swell controlling arrangement of claim 12 wherein the acid forming material is embedded within the swellable member in layers.
 15. The swell controlling arrangement of claim 12, further comprising a film in operable communication with the acid forming material and the swellable member configured to delay dilution of an acidic environment formed by the acid forming material.
 16. The swell controlling arrangement of claim 15, wherein the film includes an acid forming material.
 17. A method of controlling swelling of a swellable member, comprising: forming an acidic environment; exposing a swellable member to the acidic environment; and positioning the swellable member and the acidic environment within a swell inducing fluid.
 18. The method of controlling swelling of a swellable member of claim 17, wherein the acidic environment has a pH between 3 and
 6. 19. The method of controlling swelling of a swellable member of claim 17, further comprising diluting the acidic environment with the swell inducing fluid.
 20. The method of controlling swelling of a swellable member of claim 17, wherein the forming an acidic environment includes solutionizing acidic crystals.
 21. A swellable member comprising: a polymeric body configured to swell upon exposure to a swell inducing fluid; and an acidic material disposed at the polymeric body configured to retard a rate of swelling when the polymeric body is exposed to the swell inducing fluid.
 22. The swellable member of claim 21 wherein the acidic material is disposed in layers within the polymeric body.
 23. The swellable member of claim 21 wherein the acidic material includes crystals dispersed throughout the polymeric body. 